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Author Topic: Blown Fuse  (Read 534 times)

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Offline Why1504

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Blown Fuse
« on: April 10, 2017, 07:12:56 am »
i just attempted the high voltage test.  The fuse blew.

First, what are the specifications for the fuse? 

Second, how should I proceed?

Thanks!!


Offline Doc B.

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Re: Blown Fuse
« Reply #1 on: April 10, 2017, 07:30:48 am »
First, figure out why the fuse blew. Look over the construction in detail, checking in particular for backwards rectifiers, backwards capacitors and miswired terminals. Make sure everything is correct before you try another fuse and apply power or you could damage the power transformer. Fuse is 1.5A 250VAC 5x20mm.
Dan "Doc B." Schmalle
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Online fullheadofnothing

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Re: Blown Fuse
« Reply #2 on: April 10, 2017, 07:41:59 am »
Dan's answer on the fuse may not be correct. More information is needed, namely:

When was this kit shipped? (this could also be answered by providing the name the kit was ordered under)
« Last Edit: April 10, 2017, 07:44:54 am by fullheadofnothing »
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Offline Why1504

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Re: Blown Fuse
« Reply #3 on: April 10, 2017, 07:44:43 am »
Early March.

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Re: Blown Fuse
« Reply #4 on: April 10, 2017, 07:46:20 am »
OK. It's a 2 amp slow-blow. The fuse was increased due to some problems people had in the earlier runs, but yours is late enough that it's definitely the 2 amp.
Joshua Harris

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Offline Why1504

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Re: Blown Fuse
« Reply #5 on: April 10, 2017, 08:22:25 am »
Dan's answer on the fuse may not be correct. More information is needed, namely:

When was this kit shipped? (this could also be answered by providing the name the kit was ordered under)

Frank Perkins

Offline Why1504

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Re: Blown Fuse
« Reply #6 on: April 10, 2017, 08:30:17 am »
I have looked everything over. Does anything look out of place?

http://s90.photobucket.com/user/why1504/library/

I am about to head to the airport.  I will pick this back up Friday evening.
« Last Edit: April 10, 2017, 08:46:58 am by Why1504 »

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Re: Blown Fuse
« Reply #7 on: April 10, 2017, 08:54:59 am »
p. 40. Last paragraph.
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Offline Why1504

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Re: Blown Fuse
« Reply #8 on: April 10, 2017, 09:29:33 am »
p. 40. Last paragraph.

Please look at last photo and tell me where I messed up.

http://s90.photobucket.com/user/why1504/library/
« Last Edit: April 10, 2017, 09:39:28 am by Why1504 »

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Re: Blown Fuse
« Reply #9 on: April 10, 2017, 12:24:18 pm »
You mounted a UF4007 backwards. It is clearly visible in several of your pictures. I cannot say if it is in the last one or not; that website has repeatedly crashed my browser with all the spam.

Read the last paragraph on page 40 and look at the accompanying picture.
Joshua Harris

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Offline Chris65

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Re: Blown Fuse
« Reply #10 on: April 10, 2017, 01:13:22 pm »
Please look at last photo and tell me where I messed up.

It would be much easier to get assistance if you post photos directly on the forum, rather use those spam laden photo hosting sites!

Offline Why1504

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Re: Blown Fuse
« Reply #11 on: April 10, 2017, 01:33:03 pm »
Sorry about photobucket.  I tried to post the pictures from my iPhone and it failed.

Offline Why1504

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Re: Blown Fuse
« Reply #12 on: April 10, 2017, 02:14:06 pm »
You mounted a UF4007 backwards. It is clearly visible in several of your pictures. I cannot say if it is in the last one or not; that website has repeatedly crashed my browser with all the spam.

Read the last paragraph on page 40 and look at the accompanying picture.

I see it now.  I swear I thought the stripes were pointed the same way. Thanks. I can fix that Friday when I get back.

Offline Why1504

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Re: Blown Fuse
« Reply #13 on: April 14, 2017, 07:11:43 am »
I reversed the UF4007.  Voltages are very low.

10U  39
14U  117
15U  56

They all seemed to be falling the longer it was plugged in.

And, I just discovered the fuse blew again....
« Last Edit: April 14, 2017, 07:36:46 am by Why1504 »

Offline Caucasian Blackplate

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Re: Blown Fuse
« Reply #14 on: April 14, 2017, 08:21:39 am »
Disconnect the UF4007's where they connect to the power transformer, then perform the power transformer test with a fresh fuse.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man